The present invention relates to wire belt fasteners for use in connecting adjacent belt segments of, for example, a conveyor belt.
Hinge belt fasteners are extensively used for joining belt segments of an endless conveyor belt. Among the various types of fasteners are plate-type fasteners with upper and lower plates joined by a pair of arcuate loops and secured to a belt end with rivets or staples. As shown in U.S. Pat. Nos. 4,625,369 and 3,962,754, the plate fasteners are disposed on opposed belt ends with the arcuate loops intermeshed to define a series of aligned loops for receiving a connecting hinge pin. Some belt fasteners, such as wire fasteners, have pointed or staple-like ends to pierce the belt and form a loop extending from the belt end. A series of these belt fasteners may be secured to each end of a belt and intermeshed to provide a passage for a connecting hinge pin.
The plate fasteners described in U.S. Pat. Nos. 4,625,369 and 3,962,754 are formed from a flat sheet of metal, such as steel, in a series of steps such as cutting, punching and bending. A belt stop or abutment finger may be included with the fastener; and when formed with the fastener, it is simply a bent portion of one of the plates, generally at a right angle to that plate, and directed toward the other plate. A further example of a belt fastener, such as disclosed in U.S. Pat. No. 4,060,877, is made from a sheet metal, which is strip formed in a U-shaped arrangement having folded sides with ends which are pierced, flattened portions to receive a staple to be driven through the belt. The base of the U-shaped joint or loop, when cooperating with a series of interdigitated loops, provides a hinge pin passage to receive a hinge pin.
The present invention is directed to wire fasteners; U.S. Pat. No. 3,153,827 and U.K. Patent 2,092,031 each discloses wire fasteners which are fabricated from a wire blank. In U.S. Pat. No. 3,153,827, a circular cross section wire blank is formed into a U-shape and the ends of the wire are flattened and pierced to receive the legs of a staple, which is used to join each leg of the staple to the belt end. The present trend is to increase the belt tension on conveyors to higher and higher tensions, which must be accommodated by the wire fasteners, if they are to compete with flat plate or folded plate fasteners which provide large cross-sections of metal at the hinge pin area of the splice. If circular wire cross-sections of wire fasteners are interleaved at the hinge splice and are abutted side by side, an upper and lower cusp of space is present at which there is no metal. That is, the tangentially abutted, round wire fasteners will have substantially less metal at the splice than will a flat plate or folded plate fastener of the same lateral width. In the folded plate belt fasteners the metal has been gathered into a U-shape or the metal has been folded over onto itself to provide more metal and hence, more strength is achieved at the splice. The present invention is directed to avoiding the complex folding and forming of U-shaped cross-sections from a plate and to using a piece of wire and wire fasteners configured from wire in a manner which allows closer spacing together of the wire fasteners than the spacing achieved when using the circular cross-section wire fasteners of U.S. Pat. No. 3,153,827. With the present invention, this closer spacing allows more metal at the splice to accommodate the higher tension loads now being used.
Wire belt fasteners are produced on a large scale and must be produced economically in order to be competitive and a viable product in competition with other belt fasteners currently on the market. In the published British patent application 2,092,031, a round wire is used as a stock and it is cut on its vertical sides at the U-shaped hinge portions to provide flat vertical walls. The present invention eliminates such a cutting operation and the amount of metal which is cut from the blank and which will end up as scrap metal. Another objective of the invention is to produce belt fasteners which are substantially identical in shape with reduced tolerance variations so that the belt fasteners and staples used therewith may be easily and readily applied with automatic equipment. A still further objective of the invention is to provide wire belt fasteners with belt stops to limit belt insertion between the arms of the belt fastener.